Impact mechanism.



J. H. BALDWIN.

IMPACT MECHANISM.

APPLIOATION FILED SEPT. 23. 1910.

3 SHEETS-SHEET 1.

Patented Dec. 8, 1914-.

)vi/bneooco: M B. m,

J. H. BALDWIN.

IMPACT MECHANISM.

APPLICATION FILED SEPT. 23. 1910.

Patented Dec. 8, 1914 3 BHEETB-8HEET 2.

[ill-ll Witnesses J. H. BALDWIN. IMPACT MECHANISM. APPLICATION FILED SEPT. 23. 1910.

Patented Dec. 8, 1911 3 EEEBTB-BHEBT 3.

UNITED STATES PATENT ()FFICE.

James H. BALDWIN, or NEW YonK, N. r nssrenoa 'ro DULLES-BALDWIN ELECTRIC DRILL COMPANY, or New roan, N. Y., A CORPORATION on NEW roan.

IMPACT MECHANISM.

Specification otLetters Patent.

Application-filed eptember 253, 1910.. Serial No. 583,826.

To all whom it may concern:

Be it known that I, J AMES H. BALDWIN, a citizen of the United States, residing at New York, borough of Manhattan, county and State of New York, have invented certam new and useful Improvements in 1m act Mechanism, of which'the following is a ull, clear, and exact description.

In a common type of rock-drill the hammer or other element which strikes the drillbit or the chuck carrying the bit is actuated mechanically (in contradistinction to steam or pneumatically actuated devices), the reciprocation of the hammer being effected by a crank on the ower-driven shaft. In the operation of t e drill the natural result would be to subjectithe driving mechanism to a severe shock each time a blow is struck.

As 'such shocks are extremely injurious, means have been employed for cushioning the blow with respect to the actuating mechanism, to prevent the full force of the 1mpact from being transmitted thereto. The method usually employed for the purpose is to mount the reciprocating hammer or impact element in an air-cylinder and then connect the cylinder to the operating crank. In this construction the reciprocatory 'motion is imparted to the hammer through the instrumentality of the air in the cylinder, which air forms a highly resilient or elastic connection between the parts. This scheme is satisfactory as regards cushioning of the blow, but so ar as-I am aware no means has heretofore been proposedby which the force of the blow upon t e drill-bit can be regulated, without varying the speed or rate of the actuating mechanism.

My present invention is therefore designed to provide for easy and effective regulation of the blow, and to that end consists in the novel features of construction and combinations of elements hereinafter described, and more particularly pointed out in the appended claims.

A convenientand effective embodiment of the invention, as applied to a rock-drill of the t pe referred to, is illustrated in the annexe' drawing, and referring now thereto, Figure 1 shows the apparatus in longitudinal section. Fig. 2 is a cross section, on line II-II. Fig. 3 is a detail view of the regu lating valve and the means for operating the same. Fig. 4 isa longitudinal section illustrating my improved regulating means applied to a modified type of drill. Fig. 5 is a detail view of the regulating devices employed with said drill. Fig. 6 1s a cross section on line VI-YI. Fig. 7 is a longitudinal section illustrating another modification. Fig. 8 is a cross section on line VIII-- VIII of Fig. 7. Fig. 9 is a longitudinal section of a further modification. Fig. 10 .is a similar section of another modification.

. The bit or steel (not shown) is carried by a suitable chuck or carrier 1, slidably mounted in the drill casing 2. Similarly mounted in .the casing above the chuck is the cushioning air-cylinder or casing 3, and slidable within the same is a piston 4 having a stem 5, the whole constituting the impact element or hammer, extending through the lower or outer cylinder head 6 so as to strike the top of the chuck 1. At its top the cylinder is connected by a ,pitman 7 to a crank 8 on a driving shaft 9, rotated by any suitable motor, not shown.

In the position of the parts shown in Fig. 1 the hammer has struck a blow on the chuck, and the cylinder or casing 3 is ascending. At first, as the cylinder rises, the hammer remains stationary, creating a partial vacuum above the piston-head 4; but as the cylinder continues to rise the vacuum above thehead and the compression of the a dead center and begins to descend, the hammer also begins to fall butfloats, as it were on the air cushion beneath the piston-head. The increasing downward speed of the cylinder, however, soon equals and then exceeds the speed of the hammer resulting from gravity, so that the force of the cylinder is now exerted downwardly on the Pieton through the agency of the air above the same. The hammer is thus projected downward against the chuck.

, In the preferred construction I provide the cylinder or casing 3 with a valved airport above the piston, asfor example an ordinary pet cock such as is shown at 10 for the purpose of regulating the force of the blow, as hereafter described. As the piston, with correspondingly less power ex- For the purpose of conveniently manipu-' lating the valve to open and close the same a manuallyadjustable device 11 1s provided,

mounted preferably in the side Wall of the drill casing. In the form shown this device comprises a small knob or wheel 12 having a stem 14 rptatably mounted in a removable bearing 13 and terminating withln the casing is a fork composed of two fingers 15, 16. The plug 17 of the pet cock has a transverse operating pin or bar 18, and the positions of the valve and the operating device are preferably such that with the fork and the pin both perpendicular to the path of the cylinder, as in Fig. 1, the two Wlll Just come into contact when the cylinder is at its highest point. It will therefore be seen that if the operating device is turned, plac ing its fork in an inclined position with respect to the axis of the cylinder, as in F g. 3, the first engagement of the valve pin with the fork will depress the engaging end of the pin and so turn the valve plug, the extent of movement of the latter being of course dependent upon the adjustment'of the fork. Conversely, if the operating device is now restored to' its former position the next succeeding engagement will restore the valve plug to the corresponding position. If desired the knob 12 may be provided wlth a suitable mark, as the notch 20 on its peripher-y, to indicate the position of the fork.

In apparatus of the type described the capacity of the aircylinder or 3.1I'- CLS1I1g should, for the most eflicient operat on, be designed with due regard to the weight of the hammer which is to be used; or vice versa. With" my invention, however, by which the vacuum and the compression 1n the cylinder can be regulated, hammers of different weights can be used. This enables me to attach the bit-chuck directly to the hammer or piston; whereas otherwise the difi'erent sizes and weights of thebits used in actual work with the drill would at times render the apparatus ineflicient. The construction mentioned is illustrated in Figs.

4, 5 and 6. In these figures the stem 5 is sufiiciently long to permitthe chuck 25 to be rigidly attached to it, so that the bit or steel 26, mounted in the chuck, will be reciprocated by the piston 4 as the latter is actuated through the instrumentality of the cylinder 3 having a head-3 and the elastic or. resilient bodies of air which serve to con -nect the cylinder; and piston operatively tomenace member or bar 18, provided with a flat face to cooperate with a similarly shaped member 15* on a stem 14 rotatably mounted in the drill casing 2. For the pur-. pose of adjusting the operating device 15 the stem thereof is provided with a transverse pin 27 on the outside of the drill casing: The cylinder may, if desired, have the usual lateral ports 28. The desired intermittent rotary movement may be imparted to the stem 5 by the means illustrated in Figs. 4'and 6. For the purpose mentioned the s'tem, reciprocating in a ratchet-nut 29, is provided with one or more helical or inclined ribs 30, fitting a corre sponding groove or grooves in said nut. As the piston is raised the nut is prevented from turning by the pawl 31, and hence the coiiperating ribs and grooves cause the stem to turn; and as the piston descends the nut turns in the opposite direction, bringing the next tooth into engagement with the pawl. in this way the bit or steel is given a slight turn each time it rises.

Another modification is illustrated in Figs. 7 and 8. In this construction the stem 40 which carries the chuck (not shown) is attached to a piston 41 mounted to reciprocate in the drill casing 42. Slidably mounted on the extension 43. of this stem is 2. cylinder head 44, mounted in the end of. a cyl-' inderor casing 45 which is in turn mounted to reciprocate in the drill casing, a resilient body of air being inclosed between the piston 41 and head 44. Fixed on the end of the extension 43 is a piston 46, constructed to reciprocate inside said cylinder, orcasing 45,

and the latter is connected by its end 47 to suitable power-driven reciprocating mechanism, not shown. In the wall of the cylinder, about half-way between the head 44 and the other (open) end, one ormore ports 48 are provided, communicating with an'enlargement 49 of the inside the drill casing,

scends the ports 48 are uncovered, the com-v pression in the space 52 is relieved by the outflow of air through said ports, and air flows out of space 53 through the. passages 51; but as the cylinder or casing 45 closes the passages named the air in space 53 begins to be compressed and as the compression increases the piston 41 and stem 40 are thrown downward, with minimum resist ance by the air in space 52 since, it will be .casing' wall between the piston 41 and the head 44 is formed with a port 54 provided with a suitable valve as for example an ordinary petcock 55, by which the inflow and outflow of air through said port can be regulated, with corresponding variation in the force of the blow, as described in connection with Figs. 1 and 4.

A further modification is illustrated in Fig. 9. Here the reciprocatory cylinder or casing 60 is provided at its ends with outwardly extending flanges 61, 62, fitting the inner surface of the drill casing 63 and spacing the cylinder itselftherefrom. -At points between the cylinder flanges the drill casing is provided with inwardly extending flanges 64, 65, fitting the outer surface of the cylinder. Three annular spaces or chambers 66, 67, 68, are thus provided around the cylinder. The ends of the cylinder are closed by two heads 69, 70, the latter having a central aperture through which extends the reciprocatory chuck-stem 71, fixed at its inner end to a reciprocatory piston 72 fitting the inside of the cylinder. At each end the cylinder is provided with one or more ports 73, and at an intermediate point one or more ports 74 provide communication between the interior of the cylinder and the annular chamber 67 when the last mentioned ports are uncovered by the ment of the cylinder; As the cylinder descends the compressed air in chamber 75 flows out into the annular chamber 68, which, it will be noted, becomes larger and larger as the cylinder moves down. At the same time the port 74, overtaking the piston 72, are closed thereby, and the air in chambers 76 and 66 is compressed, throwing the piston and the stem 71 downward.- The force of the blowthus produced depends upon the degree of compression in the chambers 76 and 66 just mentioned, and for the purpose of regulating the compression, and hence the force of the blow, a port 77 is formed in the outer wall of chamber 66, said port being provided with a suitable are thus thrown wide limits. v

valve, as for example the pet cock 78,"by" which the inflow and outflow of air through the port 77 can be controlled.

in the construction illustrated in Fig.10 theair cylinder or casing finds its equivalent in a pair of spaced heads 80, 81, fitting the inner surface of the drill casing 82andconnected by a plurality of tie-rods 83 slid ing in suitable grooves 83 formed in the easing. The-head 81'is apertured to permit thechuck-stem 84 to'slide therethrough, and at-- the-innerend of the stem is fixed a piston- 85 fitting the inside of the casing. The casing wall may be provided witl1"ports--86, 'in' position to be closed and opened alternately by the respective heads. The operation is similar to that of the apparatus shown in the other figures. As the two heads rise the lower port 86 is closed by the head 81 and the air in the chamber 87, between the head 81 and the piston 85 is compressed, air flowing into the chamber 88, above the piston, through the upper port 86. As the two heads descend the upper port is closed by the head 80, resulting in compression in the 90 chamber 88, and as the lower port 86 is passed by the head 81 the compression in chamber 87 is relieved by the outflow of air through the lower ort. The piston and stem ownward. For the purpose of regulating the compression in chamber 88, and, in consequence, the force of the blow struck by the tool, the upper head may be provided with a suitable valved port, as

for example that shown, which 1s exactly like the device illustrated in Fig. 4.

The method described has proved exceedingly eilective in practical use, enabling the operator to vary the force of the blow within WVhile I have described the invention as applied to a drill, it may be used in other impact machines in which the hammer or impact element is actuated through the in-.

strumentality of an air cushioning device. It is also to be understood that the invent on is not limited to the precise construction shown, by may be embodied in other forms without departure from its proper sp rit and scope as defined in the appended claims.

1. In an impact mechanism, the combination of a piston, an air-cushion cylinder having a head said piston freely movable 1n said cylinder, a casing in which the cyl nder is axially movable, mechanism for reclprocating the ,cylinder, an air valve on the head, inside the casing, and means manually actuated from the outside of the casing for controlling said valve.

2. In an impact mechanism, the combination of a piston, an air-cushion cylinder having a head in which the piston is freely movable, a casing in which said cylinder is axially movable, mechanism for reciprocat- 130 533 p nieaeee ing the cylinder, an air valve on the head of the cylinder having an operating pin or bar, and a manually adjustable device carried by the casing in position to be engaged by said operating'pin or bar as the cylinder reaches the limit of its travel in one direction, whereby to operate thevalve according to the adjustment of said device.

3. In an impact mechanism, the combination of a piston, an air-cushion cylinder-having a head, said piston freely movable in said cylinder, a casing in which said cylinwith said valve as the cylinder is reciprocated whereby the said valve is controlled. In testimony whereof ll affix my signature in the presence of two subscribing Witnesses.

, JAMES H. BALDWIN. Witnesses:

M. LAWSON DYER,

BERT R. SANDMA-Nv 

